1. Field of the Invention
The present invention relates to a bio-molecules detecting apparatus using electromagnetic induction and a detecting method using the same. More particularly, the present invention relates to a bio-molecules detecting apparatus that detects a bio-couple by using electromagnetic induction and converting changes in mechanical properties before and after the bio-couple into electric signals, and a detecting method using the bio-molecules detecting apparatus.
2. Description of the Related Art
A bio chip is a biological micro chip that can analyze gene expression, gene distribution, and mutation by arraying and immobilizing hundreds to thousands of biomolecules, such as Deoxyribonucleic Acid (DNA), DNA fragments, and Ribonucleic Acid (RNA) whose sequences are known, on a small solid substrate formed of glass, silicon or nylon. On the bio chip, substances, that can serve as a probe for searching particular gene information of a sample, are immobilized. When the bio chip is reacted with a sample to be analyzed, a substance contained in the sample is combined with the probe, immobilized on the surface of the bio chip, thereby forming a state of hybridization. Information on a material contained in the sample can be obtained by detecting and analyzing the hybridization.
Technologies related to the bio chip include technology for attaching and immobilizing a probe, technology for detecting a signal, and technology for processing information. Currently used signal detecting methods are laser-induced fluorescence detection, electrochemical detection, mass detection, and mechanical detection.
FIGS. 1A to 1D are diagrams showing conventional bio-couple detecting methods. FIG. 1A is a diagram illustrating a conventional laser-induced fluorescence detection method. The laser-induced fluorescence detection method detects coupling of probe optically by combining a fluorescent substance with a sample and obtaining a result by using a fluorescence detecting device after a coupling reaction between the sample and the probe, and it is widely used at present. However, since the laser-induced fluorescence detection method requires a pre-processing reaction for binding the fluorescence substance with the sample prior to the coupling reaction between the sample and the probe, the sample can be lost or contaminated. Also, after the coupling reaction between the sample and the probe, it needs a complicated optical reader to detect a coupling between the sample and the probe and expensive measuring equipment. In addition, the optical detection method can hardly be miniaturized and it cannot provide a digitalized output.
FIG. 1B shows a conventional mechanical detecting device. The mechanical detection method utilizes a microassembled cantilever to measure a binding force between molecules before and after the coupling between the sample and the probe. However, the mechanical detecting device should be able to measure refraction of a cantilever beam very precisely, and it requires an additional device such as a laser for the precise measurement.
FIGS. 1C and 1D show conventional bio-molecules detecting apparatuses using a capacitor. FIG. 1C illustrates a bio-molecules detecting apparatus using a trench-type capacitor, and FIG. 1D presents bio-molecules detecting apparatus using a plane-type capacitor.
If the bio-molecules detecting apparatus utilizes changes in the characteristics of a capacitor, there is a problem in forming a small-sized capacitor. Since the capacitor is in proportion to a cross-section area and in inverse proportion to a thickness, it is difficult to design the capacitor to perform bio process easily while widening the cross-section area. The bio-molecules detecting apparatus using the trench-type capacitor, which is shown in FIG. 1C, makes the capacitor thin and widens the cross section by forming a deep trench. However, because actual gaps are very small, it is difficult to perform the bio process. FIG. 1D presents a bio-molecules detecting apparatus using a comb-like capacitor on a plane. Since the bio-molecules detecting apparatus has a thin metal film, it has problems that a small number of capacitors are formed and the bio-molecules detecting apparatus has a poor performance in detecting bio-couples.
Another conventional bio-molecules detecting apparatus uses a scanning probe microscope (SPM). The bio-molecules detecting apparatus using an SPM has a problem that it requires additional equipment such as laser equipment and photo diodes.
Another conventional bio-molecules detecting apparatus uses a piezoresistive sensor, which detects bio-couples by detecting pressure, one of basic physical quantities, with the piezoresistive sensor and converting the pressure into electric signals. However, the apparatus has a problem that it is sensitive to the surrounding environment, such as a temperature, and sensitive to procedural errors.
Another conventional bio-molecules detecting apparatus uses a laser diode/photo diode (LD/PD). The apparatus requires many manufacturing processes and high production cost.